Marker kill is allowed in jail and legit you can't just disallow it and think it will surely help. Cops keep on spawning near the area and they can get in so eaisly and won't take ages that's why in the other hand we can't have marker kill in BRs because cops may take a while to get there and it will be literally impossible for them to attempt stopping the BR.
Also, when you get in the marker I believe that you have like 5 secs protecton or more? So it's fair enough that it can't be abused. And please can you think about it more? Can you believe the amount of adminjails/punishements will be if you disallow marker kill? You do understand that there's a lot of criminals in the end of a hallway sniping and you expect them to wait for your ass to leave the marker and start arrest killing them? That's a huge no from me.
Remove kill arrest and then we can maybe work things out about this Clearly in every jail break cops end up taking over it even if there's like 100 criminals. It only takes couple of smart cops who just act like a team and do the work together. Boom jail cleared.
The jail systeme is perfect as it is right now.. Disallowing marker kill in jail will make it worse and criminals won't even enjoy jail breaking or even staying there anymore.